Well, the Skull was the one who gave him the name Crossbones, because he intended for him to be his sidekick or whatever. I guess they could introduce Crossbones without the Skull being involved, but that would be sort of strange if Cap keeps running into villains with names that reference bones.

Maybe they'll have him the leader of a military group that idolizes red skull

__________________"If you make yourself more than just a man, if you devote yourself to an ideal... you become something else entirely....A LEGEND..."